1. Field of the Invention
The present invention relates to a laminated heat exchanger and a method for producing it used as a heater core, for instance, in an air conditioner for an automobile.
2. Description of the Related Arts
As a method for producing two or more heat exchangers at a time on one assembly line, for example, what is shown in a specification and FIG. 1 through FIG. 3 of Japanese Patent Unexamined Publication No. 62-286632 is well known.
The method for producing the heat exchanger shown in the publication shows the following:
at a first process, a flat plate is formed; PA1 at a second process, a bulging portion for forming a passage and an intake opening and an outlet opening communicated with the bulging portion for forming the passage are formed a couple symmetrically in the longitudinal direction of the belt-like plate by a press; PA1 at a third process, a passage unit is constituted by bonding flush two belt-like plates, the passage unit having a pair of fluid passages into which medium flows; PA1 at a fourth process, a plurality of passage units are laminated by arranging a fin therebetween respectively, thus the intake openings being communicated, the intake openings being communicated; and PA1 at a fifth process, which is the last one, between a pair of fluid passages of the laminated passage units is cut to separate to two heat exchangers.
However, in the above mentioned method of producing heat exchanger, since the passage units is only laminated but not fixed, it is necessary to maintain the passage units provisionally by holders until brazing them.
Thus, because a longitudinal dimension of the passage unit is twice or more in comparison with what used in the case that a single heat exchanger is formed, it is necessary for the provisional maintenance by the holders to be done in two portions as both side ends in the longitudinal direction of the heat exchanger, or in three portions further added a central portion thereof, there being inconvenience of that the provisional maintenance work of the heat exchangers takes a great deal of time and labor.
Further more, both sides of every passage unit are claded with a solder member for brazing, the solder member melts in a furnace and a pair of the heat exchangers are formed.
However, in the aforementioned, as there is a problem that the holders and the passage units are connected by solder claded on the passage units, thus, it is difficult to separate the holders from the heat exchangers, a side plate and other parts being necessary to prevent connecting between the holders and the passage units, there being inconvenience like them.